This paper describes an obstacle detection system for a high-speed and agile unmanned surface vehicle (USV), running at speeds up to 30 m/s. The aim is a real-time and high performance obstacle detection system using both radar and vision technologies to detect obstacles within a range of 175 m. A computer vision horizon detector enables a highly accurate attitude estimation despite large and s...

Stability is an important concern for vehicles which move heavy loads, accelerate or brake aggressively, turn at speed, or operate on sloped terrain. In many cases, vehicles face more than one of these challenges simultaneously. Some are obliged to execute these maneuvers when their high centers of gravity leave them particularly vulnerable to tipover or rollover. A methodology is presented to ...

The focus of this study is on the attitude estimation of the four-rotor helicopter known as quadrotor. The choice of the algorithm is a complementary filter based on quaternions. For the four-rotor helicopter system has nonlinear, strong coupling, multi-variable features, it is difficult to obtain the accurate attitude values, and in order to solve this problem a quaternion-based complementary ...

With the advancements in micro-electromechanical systems (MEMS) technologies, magnetic and inertial sensors are becoming more and more accurate, lightweight, smaller in size as well as low-cost, which in turn boosts their applications in human movement analysis. However, challenges still exist in the field of sensor orientation estimation, where magnetic disturbance represents one of the obstac...

This paper presents the design and performance evaluation of a novel integrated attitude filter with application to space navigation. The design is based directly on the sensor measurements as opposed to traditional solutions that resort to rotation parameterizations. The information provided by a low-cost star tracker is merged with the measurements of a triaxial rate gyro to provide accurate ...

This paper presents an extension to the classical Cones Intersection Technique, which was, and is, exhaustively used to estimate the spin axis direction of spin stabilized spacecraft. The resulting Optimal Cones Intersection Technique is derived from a demonstrated co-planarity condition and does not present ambiguities or singularities. The proposed method allows an optimal estimation of any o...

This paper presents an aircraft attitude and heading estimator using catadioptric images as a principal sensor for UAV or as a redundant system for IMU (Inertial Measure Unit) and gyros sensors. First, we explain how the unified theory for central catadioptric cameras is used for attitude and heading estimation, explaining how the skyline is projected on the catadioptric image and how it is seg...

Navigation employing low cost MicroElectroMechanical Systems (MEMS) sensors in Unmanned Aerial Vehicles (UAVs) is an uprising challenge. One important part of this navigation is the right estimation of the attitude angles. Most of the existent algorithms handle the sensor readings in a fixed way, leading to large errors in different mission stages like take-off aerobatic maneuvers. This paper p...

In this paper, two different algorithms are presented for the estimation of spacecraft body angular rates in the absence of gyro rate data for a star tracker mission. In first approach, body angular rates are estimated with the spacecraft attitude using a dynamical model of the spacecraft. The second approach makes use of a rapid update rate of star camera to estimate the spacecraft body angula...